Abstract 326: Nucleostemin Induced by Pim-1 Kinase Antagonizes Senescence of Cardiac Progenitor Cells

Decline in stem cell functionality and regenerative capability is a crucial contributor to aging, upon which the c-kit+ cardiac progenitor cell (CPC) pool with enhanced regenerative potential decreases and CPCs with limited proliferative and differentiation potential progressively accumulate. With cardiac stem cells currently being used in the clinic, especially in the elderly population, there is a dire need to understand the phenotypic, molecular and functional characteristics of senescent stem cells to effectively manipulate them for therapy. Nucleostemin (NS), a nucleolar stress sensor protein associated with stem cell pluripotency and regeneration declines upon cardiac aging. We hypothesize that NS is a critical antagonizer of senescence in CPCs. NS expression decreases significantly (-59%, p<0.05), while the % of senescent cells increases in CPCs isolated from old mice (13 month, OCPC) relative to CPCs isolated from young mice (3 month, YCPC). OCPCs are morphologically different, characterized by fl...